The present invention relates in general to mineral mining installations and, more particularly, to apparatus for controlling the position of a mineral mining or winning machine movable along guide means.
One form of control apparatus, described in German patent specification No. 2 319 910, uses hydraulic piston and cylinder units connected between the guide means and elongate beams pivotable in relation to the guide means and guided on roof supports. In this known construction the guide means takes the form of a scraper-chain conveyor having a machine guide on its mineral-face side and the units are coupled to brackets on the conveyor goaf side. Similar known control apparatuses are also described in U.S. Pat. Nos. 4,045,089 and 4,186,969. In these known constructions the piston and cylinder units, which are used to tilt the conveyor and its guide into various inclinations, are connected to the beams at positions spaced outwardly from the conveyor relative to the positions at which the beams connect with the brackets. The beams are usually guided at their ends remote from the conveyor for movement in the direction of advancement of the conveyor and the machine and shifting rams act on the conveyor via the beams to advance the latter to follow the winning progress. The beams are restrained from vertical movement at their rear ends although swinging or angular mobility is permitted. The beams also serve to align and guide the roof supports when these are drawn up to follow the advancement of the conveyor. There is a direct relationship between the stroke of the piston and cylinder units and the inclination of the conveyor and its guide and this is not influenced to any great extent by unevenness in the level of the floor of the mine working since the contact zones between the floor and the various parts of the mine installation are well spaced apart. The known forms of control apparatus have generally performed well but their main disadvantage is that the space between the conveyor and the roof supports tends to become restricted and access is difficult. Moreover, the known positioning of the piston and cylinder units tends to produce a fairly low torque for adjusting the guide position because there is a relatively short fulcrum lever distance and, to compensate, a large number of units may need to be provided for heavy-duty constructions.
A general object of the present invention is to provide an improved form of control apparatus.